Synthesis, Characterization, and Biological Evaluation of N-Methyl Derivatives of Norbelladine
Bibliographic record
Abstract
Norbelladine derivatives have garnered attention in recent years due to their diverse biological activities and pivotal role in the biosynthetic pathway of Amaryllidaceae alkaloids. This study reports the synthesis and biological evaluation of four O,N-methylated derivatives of norbelladine. These derivatives were synthesized through a three-step process: forming imine intermediates from benzaldehydes with tyramine, hydrogenating them to secondary amines, and N-methylating these amines. The products were purified and characterized by 1H and 13C NMR spectroscopy. Their biological activities were assessed by evaluating their ability to inhibit Alzheimer’s disease-related enzymes acetylcholinesterase and butyrylcholinesterase. Additionally, the cytotoxic activity of the novel derivatives was tested against cancer cell lines derived from hepatocarcinoma (Huh7), adenocarcinoma (HCT-8), and acute myeloid leukemia (THP-1) cells, and their antiviral properties against a human coronavirus (HCoV-OC43), a flavivirus (dengue virus), and a lentivirus (pseudotyped HIV-1). Docking analysis was performed to understand the impact of the N-methylation on their pharmacological relevance. The results indicate that while N-methylation does not significantly affect antiviral activity, it enhances butyrylcholinesterase inhibition for N-methylnorbelladine and 4′-O,N-dimethylnorbelladine. Overall, this work enhances our understanding of norbelladine derivatives, provides new tools for Alzheimer’s disease research, and lays the groundwork for future pharmaceutical developments.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".